PLEASE HELP! Vista has locked me out!

Hello, Please, please help me! My Acer (that came with Vista already installed) will not let anyone log on. My boyfriend installed the updates from the disc that came with the computer and then restarted it. Ever since then we have not been able to log on. It keeps saying user name or password incorrect. I know for a fact that we didn't change the password. I tried booting it from a back up disc and I even paid $24.00 for windows logon key 6.0 (kinda think that was just a scam). I started in safe mode and everything. I tried to log on as administrator and as a guest and all of our accounts say that they have been disabled. Is there anything I can do to get into my computer? I have no password change disc. I have been looking for a solution to this problem for 2 days now and I'm so sick of it. I have to keep unhooking the Acer and hooking to this computer just to get online to keep looking for other things to try. Please help!?!

 

Thanks! I'm back on my computer again, yay!